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Message-Id: <20221115011943.1051039-1-ira.weiny@intel.com>
Date: Mon, 14 Nov 2022 17:19:43 -0800
From: ira.weiny@...el.com
To: Dan Williams <dan.j.williams@...el.com>,
Bjorn Helgaas <bhelgaas@...gle.com>
Cc: Ira Weiny <ira.weiny@...el.com>,
Bjorn Helgaas <helgaas@...nel.org>,
Gregory Price <gregory.price@...verge.com>,
Jonathan Cameron <Jonathan.Cameron@...wei.com>,
Alison Schofield <alison.schofield@...el.com>,
Vishal Verma <vishal.l.verma@...el.com>,
Ben Widawsky <bwidawsk@...nel.org>, linux-cxl@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org
Subject: [PATCH] PCI/doe: Fix work struct declaration
From: Ira Weiny <ira.weiny@...el.com>
The callers of pci_doe_submit_task() allocate the pci_doe_task on the
stack. This causes the work structure to be allocated on the stack
without pci_doe_submit_task() knowing. Work item initialization needs
to be done with either INIT_WORK_ONSTACK() or INIT_WORK() depending on
how the work item is allocated.
Jonathan suggested creating doe task allocation macros such as
DECLARE_CDAT_DOE_TASK_ONSTACK().[1] The issue with this is the work
function is not known to the callers and must be initialized correctly.
A follow up suggestion was to have an internal 'pci_doe_work' item
allocated by pci_doe_submit_task().[2] This requires an allocation which
could restrict the context where tasks are used.
Compromise with an intermediate step to initialize the task struct with
a new call pci_doe_init_task() which must be called prior to submit
task.
[1] https://lore.kernel.org/linux-cxl/20221014151045.24781-1-Jonathan.Cameron@huawei.com/T/#m88a7f50dcce52f30c8bf5c3dcc06fa9843b54a2d
[2] https://lore.kernel.org/linux-cxl/20221014151045.24781-1-Jonathan.Cameron@huawei.com/T/#m63c636c5135f304480370924f4d03c00357be667
Cc: Bjorn Helgaas <helgaas@...nel.org>
Reported-by: Gregory Price <gregory.price@...verge.com>
Reported-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
Suggested-by: Dan Williams <dan.j.williams@...el.com>
Signed-off-by: Ira Weiny <ira.weiny@...el.com>
---
drivers/cxl/core/pci.c | 2 ++
drivers/pci/doe.c | 14 ++++++++++++--
include/linux/pci-doe.h | 8 +++++---
3 files changed, 19 insertions(+), 5 deletions(-)
diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
index 9240df53ed87..a19c1fa0e2f4 100644
--- a/drivers/cxl/core/pci.c
+++ b/drivers/cxl/core/pci.c
@@ -525,6 +525,7 @@ static int cxl_cdat_get_length(struct device *dev,
DECLARE_CDAT_DOE_TASK(CDAT_DOE_REQ(0), t);
int rc;
+ pci_doe_init_task(cdat_doe, &t.task, true);
rc = pci_doe_submit_task(cdat_doe, &t.task);
if (rc < 0) {
dev_err(dev, "DOE submit failed: %d", rc);
@@ -554,6 +555,7 @@ static int cxl_cdat_read_table(struct device *dev,
u32 *entry;
int rc;
+ pci_doe_init_task(cdat_doe, &t.task, true);
rc = pci_doe_submit_task(cdat_doe, &t.task);
if (rc < 0) {
dev_err(dev, "DOE submit failed: %d", rc);
diff --git a/drivers/pci/doe.c b/drivers/pci/doe.c
index e402f05068a5..cabeae4ae955 100644
--- a/drivers/pci/doe.c
+++ b/drivers/pci/doe.c
@@ -319,6 +319,7 @@ static int pci_doe_discovery(struct pci_doe_mb *doe_mb, u8 *index, u16 *vid,
};
int rc;
+ pci_doe_init_task(doe_mb, &task, true);
rc = pci_doe_submit_task(doe_mb, &task);
if (rc < 0)
return rc;
@@ -495,6 +496,14 @@ bool pci_doe_supports_prot(struct pci_doe_mb *doe_mb, u16 vid, u8 type)
}
EXPORT_SYMBOL_GPL(pci_doe_supports_prot);
+void pci_doe_init_task(struct pci_doe_mb *doe_mb, struct pci_doe_task *task,
+ bool onstack)
+{
+ task->doe_mb = doe_mb;
+ __INIT_WORK(&task->work, doe_statemachine_work, onstack);
+}
+EXPORT_SYMBOL_GPL(pci_doe_init_task);
+
/**
* pci_doe_submit_task() - Submit a task to be processed by the state machine
*
@@ -517,6 +526,9 @@ int pci_doe_submit_task(struct pci_doe_mb *doe_mb, struct pci_doe_task *task)
if (!pci_doe_supports_prot(doe_mb, task->prot.vid, task->prot.type))
return -EINVAL;
+ if (WARN_ON_ONCE(task->work.func != doe_statemachine_work))
+ return -EINVAL;
+
/*
* DOE requests must be a whole number of DW and the response needs to
* be big enough for at least 1 DW
@@ -528,8 +540,6 @@ int pci_doe_submit_task(struct pci_doe_mb *doe_mb, struct pci_doe_task *task)
if (test_bit(PCI_DOE_FLAG_DEAD, &doe_mb->flags))
return -EIO;
- task->doe_mb = doe_mb;
- INIT_WORK(&task->work, doe_statemachine_work);
queue_work(doe_mb->work_queue, &task->work);
return 0;
}
diff --git a/include/linux/pci-doe.h b/include/linux/pci-doe.h
index ed9b4df792b8..457fc0e53d64 100644
--- a/include/linux/pci-doe.h
+++ b/include/linux/pci-doe.h
@@ -31,8 +31,8 @@ struct pci_doe_mb;
* @rv: Return value. Length of received response or error (bytes)
* @complete: Called when task is complete
* @private: Private data for the consumer
- * @work: Used internally by the mailbox
- * @doe_mb: Used internally by the mailbox
+ * @work: Used internally by the mailbox [see pci_doe_init_task()]
+ * @doe_mb: Used internally by the mailbox [see pci_doe_init_task()]
*
* The payload sizes and rv are specified in bytes with the following
* restrictions concerning the protocol.
@@ -53,7 +53,7 @@ struct pci_doe_task {
void (*complete)(struct pci_doe_task *task);
void *private;
- /* No need for the user to initialize these fields */
+ /* Call pci_doe_init_task() for these */
struct work_struct work;
struct pci_doe_mb *doe_mb;
};
@@ -72,6 +72,8 @@ struct pci_doe_task {
struct pci_doe_mb *pcim_doe_create_mb(struct pci_dev *pdev, u16 cap_offset);
bool pci_doe_supports_prot(struct pci_doe_mb *doe_mb, u16 vid, u8 type);
+void pci_doe_init_task(struct pci_doe_mb *doe_mb, struct pci_doe_task *task,
+ bool onstack);
int pci_doe_submit_task(struct pci_doe_mb *doe_mb, struct pci_doe_task *task);
#endif
base-commit: 30a0b95b1335e12efef89dd78518ed3e4a71a763
--
2.37.2
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